Cyanoalkyl phosphates and method of preparation



Patented Jan. 10, 1950 UNHTED STATES FATE CYANOALKYL PHOSPHATES ANDMETHOD OF PREPARATION Jack T. Cassaday assignor to and Erick I.Hoegberg, Stamford, and Bruce D. Gleissner,

Riverside, Comp,

American Cyanamld Company, New York, N. Y., a corporation of Maine NoDrawing. Application January 12, 1949, Serial No. 7050i i. in which R1and R2 are chosen from the group consisting of allql and arylhydrocarbon radicals and X is a member of the group consisting of sulfurand oxygen.

In the new compounds R1 or R2 may be the same or difierent radicals.Furthermore, it is to be understood that when R1 and R2 stand for alkylradicals, they represent both the straight chain and branch chain, thesaturated and unsaturated, and the cycloaliphatic hydrocarbon radicals.Typical examples of these radicals are methyl, ethyl, n propyl,isopropyl, isobutyl, sec.-amyl, nhewl, Z-ethylhexyl, n-octyl, n-decyl,n-dodecyl, oleyl, cetyl, ceryl, allyl, cyclohexyl, phenyl and naphthyl.

The compounds of this invention possess general pest-controlcharacteristics, including insecticidal, rodenticidal, and fungicidalproperties.

They may also be employed as corrosion inhibitors, plasticizers,flotation agents, and petroleum additives.

The phosphate esters of the above general formula may be readilyprepared by reacting a, phosphate of the formula H Z( ,--CN

i in which Z is a. member Of of chlorine and bromine.

The term alkali-forming metal as used in this specification and in theappended claims is inthe group consisting 2 tended to cover the alkalimetals (including am monium), and the alkaline earth metals.

A typical reaction in which potassium 0,0-diethyl dithiophosphate isreacted with monobromoacetonitrile to produce S-cyanomethyl 0,0- diethyldithiophosphate may be illustrated as follows:

High yields of the desired products are obtained by carrying out thereaction in the presence of a solvent. Such solvents include the lowmolecular we ght aliphatic monohydric alcohols, the ketones such as, forexample, acetone, methyl ethyl ketone, methyl isobutyl ketone, methylbenzyl ketone, cyclohexanone, acetophenone, and the like; aliphaticesters such as ethyl acetate, amyl acetate, 2-ethylhexy1, acetate,methyl proprionate, methyl butyrate, ethyl butyrate and isopropylbutyrate; dioxane, nitrobenzene, chlorobenzene, toluene, xylene,chloroform, carbon tetrachloride, 1,2-dimethoxyethane and the trialkylphosphates such as trimethyl phosphate, triethyl phosphate andtriisopropyl phosphate.

-The reaction is preferably carried out at a temperature within therange of from about 20 C. to, 0. However, temperatures outside of thisrange may be employed depending upon the type of reactants and solventsutilized.

An alternative method of preparing the above compounds consists inemploying in lieu of the alkali-forming metal phosphate thecorresponding acid and a basic alkali-forming metal compound, the latterhaving suflicient alkalinity to neutralize said acid. Obviously, thisprocedure avoids the initial preparation and isolation of thealkali-forming metal phosphate. Such basic alkali-forming metalcompounds include sodium carbonate, potassium carbonate, bariumcarbonate, magnesium carbonate, lithium carbonate, sodium hydroxide,potassium hydroxide, calcium hydroxide, strontium hydroxide, magnesiumhydroxide, sodium hydrosulfide, sodium borate, tripotassium arsenate,tripotassium arsenite, sodium pyrophosphate, magnesium pyrophosphate,potassium pyrophosphate, barium phosphate. trisodium phosphate, and thelike.

Employing-the above procedure in the preparation of S -cyanomethyl0,0-di-n-butyl dithiophosphate, the reaction may be illustrated asfollows:

The following examples in which the parts are a by weight furtherillustrate the invention.

Example 1 The procedure of Example 1 was employed, using 20.8 parts ofsodium 0,0-diethyl dithiophosphate, 12 parts of monobromoacetonitrileand 100 parts of acetone. The mixture was allowed to stand at roomtemperature for 2 days.

The product, S-cyanomethyl 0,0-diethyl dithiophosphate, was anamber-colored liquid, having a refractive index Np 1.5153.

Example 3 The procedure of Example 1 was employed, using 8.9 parts ofpotassium 0,0-diphenyl dithiophosphate, 2.2? parts ofmonochloroacetonitrile and 100 parts of acetone. The mixture was allowedto stand at room temperature for 2 days. The product, S-cyanomethyl0,0-diphenyl dithiophosphate, was an amber-colored oily liquid having arefractive index ND 1.5180.

Example 4 The procedure of Example 1 was employed, using 15.4 parts ofpotassium 0,0-di-n-amyl dithiophosphate, 3.8 parts ofmonochloroacetonitrile and 100 parts of acetone. The product,

suspended in 100 parts of ethanol. 15.1 parts of monochloroacetonitrilewere then added slowly and the mixture was heated under reflux withstirring for a period of 6 /2 hours. The reaction mixture was filteredand the filtrate was heatbd under vacuum to distill off the ethanol. Theresidual oily liquid was washed with cold water and dried over anhydroussodium sulfate. 3'1 parts of the product, S-cyanomethyl 0,0-diethyldithiophosphate, were obtained.

Example 7 The procedure of Example 6 was employed, using 41 parts of0,0-di-n-decyl dithiophosphoric acid, 7.9 parts of sodium hydrosulflde(71%), 200 parts of acetone and 12 parts of monobromoacetonitrile. Themixture was not heated under reflux as in Example 6, but was allowed tostand for 2 days at room temperature. The product, 8- cyanomethyl0,0-di-n-decyl dithiophosphate, was obtained in a 93% yield as a redoily liquid.

The phosphate esters of this invention may be employed in controllingmany types of insects and mites such as, for example, the black beanaphid, green peach aphid, pea aphid, chrysanthemum aphid, greenhousethrips, California red scale, citrus red spider, greenhouse red spider,milkweed bug, mealy bug, sow bug, German cock- 1 roach, Southern armyworm, yellow fever mosquito, malarial mosquito, Mexican bean beetle,confused flour beetle, and black carpet beetle.

These new compounds may also be used in combination with insecticidessuch as lead atsenate, nicotine, rotenone, pyrethrum, benzenehexachloride, 1,1,1 trichloro 2,2 di (p chlorophenyl) ethane, dodecylthiocyanate, phenothiazine, and the like; with fungicides such assulfur, various copper compounds, mercury salts, and the like; and withvarious types of plant foods and fertilizers.

This application is a continuation-in-part of our copending applicationSerial Number 6348, filed February 4, 1948.

While the invention has been described with particular reference tospecific embodiments, it

is .tO be understood that it is not to be limited S-cyanomethyl0,0-di-n-amyl dithiophosphate,

was a straw-colored liquid having a refractive index N19 1.4984.

Example 5 The procedure of Example 1 was employed, using 20.8 parts ofpotassium 0,0-diethyl monothiophosphate, 12 parts ofmonobromoacetonitrile and 75 parts of methyl isobutyl ketone. Themixture was held at C. for 5 hours and then cooled and filtered toremove the precipitated potassium bromide. 12 parts of S-cyanomethyl0,0-diethyl monothiophosphate were obtained as a brown oily liquid.

Example 6 40 parts of 0,0-diethyl ditbiophosphorlo (93%) were addedslowly to a well-agitated mixture of 21.2 parts of anhydrous sodiumcarbonate thereto, but is to be construed. broadly and restricted solelyby the scope of the appended claims.

We claim: 1. Phosphate esters of the general formula R1 .5 H =i-B-i-CNxt-s-Ju-ou it in which R1 and R2 are chosen from the group consisting ofalkyl and aryl hydrocarbon radi cals', and X is a member of the groupconsisting of sulfur and oxygen, and Y represents an alkaliformingmetal, with a halogen-substituted acetonitrile of the formula in which Zis a member of the group consisting of chlorine and bromine.

6. The method of claim 5 in which the reaction is carried out in thepresence of a solvent.

7. The method of claim 5 in which the reaction is carried out at atemperature within the range of from about 20 C. to 150 C.

8. A method of preparing a phosphate ester of the general formula inwhich R1 and R2 are chosen from the up consisting of alkyl and arylhydrocarbon radicals, and X is a member of the group consisting ol'sulfur and oxygen, which includes the step oi reacting together ahalogen-substituted aceto nitrile of the formula in which Z is a memberof the group consisting of chlorine and bromine, an acid phosphate ofthe general formula in which R1 and R2 are chosen from the groupconsisting of alkyl and aryl hydrocarbon radicals, and X is a member ofthe group consisting of sulfur and'oxygen, and a basic alkali-formingmetal compound having suflicient alkalinity to neutralize the acidphosphate.

9. The method of claim 8 in which the basic alkali-forming metalcompound is sodium carbonate.

10. The method of claim 8 in which the reaction is carried out in thepresence of a solvent.

11. A method of preparing S-cyanomethyl 0,0-diethyl -dithiophosphatewhich includes the step of reacting together 0,0-diethyldithiophosphoric acid, sodium carbonate and monochloroacetonitrile inthe presence of ethyl alcohol.

12. A method of preparing S-cyanomethyl 0,0-dipheny1 dithiophosphatewhich includes the step of reacting together potassium 0,0-diphenyldithiophosphate and monochloroacetonitrile in the presence of acetone.

13. A method of preparing S-cyanomethyl 0,0-diethyl monothiophosphatewhich includes the step of reacting together potassium 0,0-dlethylmonothiophosphate and monobromoacetw nitrlle in the presence of methylisobutyl ketone.

JACK T. CASSADAY.

ERICK I. HOEGBERG. BRUCE D. GLEISS.

No references cited.

1. PHOSPHATE ESTERS OF THE GENERAL FORMULA